I did open up a service request with vmware , got it resolved, but it come up again.

What are your toughts on this error/ warning

Bootbank cannot be found at path '/bootbank' (2015-09-08T01:01:01.958Z cpu21:436781)

warning

07/09/2015 9:01:01 PM

esxi2.domain.net (*renamed)

Configuration IssuesLost connectivity to the device MPX.vmhba32:C0:T0:L0 backing the boot filesystem /vmfs/devices/disks.mpx.vmhba32:C0:T0:L0. As a result, host configuration changes will not be saved to persistent storage.

** oddly enought i have to write it down as i cant do a cut and paste from vcenter.

The first and most obvious question: When it happened last time, what was the root cause and what did VMware recommend to fix the issue? Have you tried those steps again?

Error "Lost connectivity to the device MPX.vmhba32:C0:T0:L0 backing the boot filesystem" suggests to me you've got ESXi installed on a thumb drive or SD card, and the media might be failing. Can you give further detail about your ESXi install?﻿